Grass treatment devices are used for treating grass surfaces such as lawns, playing fields, parkland and golf courses. Types of grass treatment device include, but are not limited to, mowers, rollers, scarifiers, and spikers.
In certain applications, the height of the grass treatment tool is critical. For example, when mowing a golf green the mower blades must, in some circumstances, be at a specified height above the grass to an accuracy of within 0.25 mm. Other grass treatment devices must, in some circumstances be accurate to a similar degree.
Grass treatment tools are usually mounted on a grass treatment device. For many prior art grass treatment machines, such as those manufactured by John Deere, Toro or Jacobsen, three grass treatment devices are mounted on one machine in a reverse echelon disposition having two grass treatment devices at the front of the machines in the direction of travel, and a third grass treatment device mounted behind the first two.
Referring to FIG. 1 herein, there is illustrated schematically the disposition of grass treatment devices on a known grass treatment machine. A first grass treatment device 101 is disposed adjacent to a second grass treatment device 102. A third grass treatment device 103 is disposed behind the first 101 and second 102 grass treatment devices relative to the direction of travel 104 of the grass treatment machine. The third grass treatment device 103 is provided to ensure that the grass surface to be treated in the space 105 between the first grass treatment device 101 and the second grass treatment device 102 is also treated, by the third grass treatment device 103.
Referring to FIG. 2 herein, there is illustrated schematically a side elevation view of a prior art grass treatment device. The grass treatment device 201 comprises a frame having two end panels disposed either side of a pair of rollers and a grass treatment tool. A first end panel 202 has a grass treatment tool 203 mounted on it. The grass treatment tool 203 may also include any suitable grass treatment tool, such as a roller, a mower, a scarifier or a spiker.
A first roller 204 is disposed towards the front of the first end panel 202 relative to the direction of travel of the grass treatment machine. A second roller 205 is disposed towards the rear of the first end panel 202 relative to the direction of travel of the grass treatment machine. The rollers are provided to assist in smooth movement of the grass treatment device 201 over the grass surface 200, and to maintain a constant height of the grass treatment tool 203 relative to the grass surface 200. The grass treatment device 201 further comprises means 206 to attach the grass treatment device 201 to the grass treatment machine. A second end panel (not shown) is disposed opposite the first end panel 202 at the opposite ends to the rollers 204, 205 and the grass treatment tool 203.
For known grass treatment devices 201, the height 207 of the grass treatment tool 203 relative to the grass surface 200 can be adjusted by altering the distance of the first roller 204 relative to the first end panel 202.
The adjustment means to adjust the distance of the first roller 204 relative to the first end panel 202, also referred to as an “adjuster,” comprises a first bracket 208 disposed on the end panel 202 towards the front of the first end panel 202 relative to the direction of travel of the grass treatment machine, and a second bracket 209 attached to the first roller 204. The first bracket 208 is operatively connected to the second bracket by means of a threaded shaft 210. An upper portion of the threaded shaft 210 comprises a handle 211.
By turning the handle 211, the threaded shaft 210 rotates about its longitudinal axis and the distance of the second bracket 209 from the first bracket 208 can be adjusted. In this way, the distance of the first roller 204 relative to the first end panel 202 can be adjusted. This adjustment must be made both at the first end panel 202, and at the second end panel (not shown) disposed at the opposite end of the first roller 204.
A first locking nut 212 is disposed about the threaded bar 210 above the first bracket 208, and a second locking nut 213 is disposed about the threaded bar 210 below the second bracket. By tightening the locking nuts 212, 213, the position of the first roller 204 relative to the first end panel 202 can be temporarily fixed.
By altering the distance of the first roller 204 relative to the first end panel 202, the height 207 of the grass treatment tool 203 relative to the grass surface is also altered.
Problems with this system include the necessity for taking a measurement of the first roller 204 relative to the first end panel 202 during the process of adjusting the distance of the first roller 204 relative to the end panel 202. This can necessitate taking many measurements as the adjustment is being made to ensure that the correct distance is set.
Furthermore, there is a greater margin for error when taking these measurements as the distance can vary either side of the desired distance depending on the way in which the distance is measured. This can be a significant problem when adjusting the distance of the first roller 204 relative to the first end panel 202 and the second end panel (not shown), as differences in the distance could lead to the grass treating tool 203 being disposed at an angle relative to the grass surface, leading to uneven grass treatment.
Furthermore, when tightening the locking nuts 212, 213, the required distance of the first roller 204 relative to the first end panel 202 can be fractionally altered from the required distance.